﻿using System;
using System.Windows;
using System.Windows.Input;

namespace YsTiffConverter.ViewModel
{
    /// <summary>
    /// Extends ICommand interface for work with Model View.
    /// </summary>
    internal class CommandProxy : Freezable, ICommand
    {
        /// <summary>
        /// Initializes a new instance of the CommandProxy class.
        /// </summary>
        /// <returns></returns>
        protected override Freezable CreateInstanceCore()
        {
            return new CommandProxy();
        }

        /// <summary>
        /// Registers the CommandProxy interface.
        /// </summary>
        public static readonly DependencyProperty CommandProperty =
            DependencyProperty.Register("Command",
                typeof(ICommand),
                typeof(CommandProxy),
                new UIPropertyMetadata());

        /// <summary>
        /// Gets or sets the command.
        /// </summary>
        public ICommand Command
        {
            get
            {
                return (ICommand)GetValue(CommandProperty);
            }
            set
            {
                SetValue(CommandProperty, value);
            }
        }

        /// <summary>
        /// Is calling when a caller wants to execute a command.
        /// </summary>
        /// <param name="parameter">A command parameter.</param>
        public void Execute(object parameter)
        {
            Command.Execute(parameter);
        }

        /// <summary>
        /// Is calling when a caller wants to know, if a command may be executed.
        /// </summary>
        /// <param name="parameter">A command parameter.</param>
        public bool CanExecute(object parameter)
        {
            return Command != null && Command.CanExecute(parameter);
        }

        /// <summary>
        /// Refelects adding or deleting an event handler.
        /// </summary>
        public event EventHandler CanExecuteChanged
        {
            add
            {
                CommandManager.RequerySuggested += value;
            }
            remove
            {
                CommandManager.RequerySuggested -= value;
            }
        }
    }

}
